Process for producing poly(arylene sulfide), and poly(arylene sulfide) comprising contacting a wash liquid with an alkaline compound

Abstract

Disclosed is a process for producing poly(arylene sulfide) which includes: a polymerization step of polymerizing a dihalogenated aromatic compound and at least one sulfur source selected from the group consisting of alkali metal sulfides and alkali metal hydrogen sulfides in an organic amide solvent, preferably in the presence of a phase separating agent; a separation step of separating a polymer from a reaction liquid containing a produced polymer after the polymerization step; a washing step of washing the polymer with a washing liquid that consists of water and/or an organic solvent; and a separated liquid treatment step of bringing both a separated liquid that has been recovered after the separation of the polymer in the separation step and a separated liquid containing a wash waste liquid that has been recovered after the separation of the polymer in the washing step into contact with an alkaline compound. Also disclosed is poly(arylene sulfide).

The invention claimed is: 
     
       1. A process for producing poly(arylene sulfide), the process comprising:
 a polymerization step of polymerizing a dihalogenated aromatic compound and at least one sulfur source selected from the group consisting of alkali metal sulfides and alkali metal hydrogen sulfides in an organic amide solvent to produce a polymer; 
 a separation step of separating and recovering polymer from a reaction liquid containing the produced polymer after the polymerization step; 
 a washing step of washing the recovered polymer with at least one washing liquid selected from the group consisting of water, an organic solvent, and a mixture solution of water and an organic solvent, wherein the organic solvent comprises acetone; and 
 a separated liquid treatment step of bringing a separated liquid containing a wash waste liquid obtained after separating the polymer in the washing step and a polymer-separated liquid obtained after separating the polymer in the separation step into contact with an alkaline compound, wherein the step for treating the separated liquid is carried out until the pH of the separated liquid is in the range of 10.6 to 13.8, and wherein the separated liquid after the separated liquid treatment step is subjected to distillation and an organic solvent and/or an organic amide solvent is recovered and reused for the process for producing poly(arylene sulfide). 
 
     
     
       2. The process for producing poly(arylene sulfide) according to  claim 1 , wherein the alkaline compound is alkali metal hydroxide. 
     
     
       3. The process for the production of poly(arylene sulfide) according to  claim 2 , wherein the alkali metal hydroxide is sodium hydroxide. 
     
     
       4. The process for producing poly(arylene sulfide) according to  claim 1 , wherein the amount of the alkaline compound used is 0.001 to 10 parts by mass per 100 parts by mass of the separated liquid. 
     
     
       5. The process for producing poly(arylene sulfide) according to  claim 1 , wherein the polymerization step is a polymerization reaction of at least one sulfur source selected from the group consisting of the alkali metal sulfides and the alkali metal hydrogen sulfides with the dihalogenated aromatic compound in the organic amide solvent at the temperature of 170 to 290° C. in the presence of a phase separating agent. 
     
     
       6. The process for producing poly(arylene sulfide) according to  claim 5 , wherein the phase separating agent is at least one selected from the group consisting of water, metal salts of organic carboxylic acids, metal salts of organic sulfonic acids, alkali metal halides, alkali earth metal halides, alkali earth metal salts of aromatic carboxylic acid, alkali metal salts of phosphoric acid, alcohols, and paraffinic hydrocarbons. 
     
     
       7. The process for producing poly(arylene sulfide) according to  claim 6 , wherein the phase separating agent is 0.5 to 10 mol of water and 0.001 to 0.7 mol of metal salts of organic carboxylic acid per 1 mol of the charged sulfur source. 
     
     
       8. The process for producing poly(arylene sulfide) according to  claim 1 , wherein the polymerization step is a polymerization reaction of at least one sulfur source selected from the group consisting of the alkali metal sulfides and the alkali metal hydrogen sulfides with the dihalogenated aromatic compound in the organic amide solvent at the temperature of 170 to 270° C., and at the point of time, in which the conversion rate of the dihalogenated aromatic compound has reached 30% or more, the phase separating agent is included in the polymerization reaction system and the polymerization reaction is further continued at the temperature of 245 to 290° C. 
     
     
       9. The process for producing poly(arylene sulfide) according to  claim 1 , wherein the polymerization step is a polymerization process with at least two stages which comprises:
 first-stage polymerization step by which at least one sulfur source selected from the group consisting of the alkali metal sulfides and the alkali metal hydrogen sulfides is subjected to the polymerization reaction with the dihalogenated aromatic compound in the organic amide solvent to produce a polymer in which conversion rate of the dihalogenated aromatic compound is 80 to 99%; and 
 second-stage polymerization step by which the polymerization reaction is continued in a phase-separated state, wherein a concentrated phase of the produced polymer and a dilute phase of the produced polymer are co-present as a mixture, in the presence of a phase separating agent in the polymerization reaction system. 
 
     
     
       10. The process for producing poly(arylene sulfide) according to  claim 1 , wherein the polymerization step is a polymerization process with at least two stages which comprises:
 first-stage polymerization step by which at least one sulfur source selected from the group consisting of the alkali metal sulfides and the alkali metal hydrogen sulfides is subjected to the polymerization reaction with the dihalogenated aromatic compound in the organic amide solvent at the temperature of 170 to 270° C. in the presence of water in an amount of 0.02 to 2.0mol per 1 mol of the charged sulfur source to produce a polymer in which conversion rate of the dihalogenated aromatic compound is 80 to 99%; and 
 second-stage polymerization step by which water content in the polymerization reaction system is controlled such that water is present in an amount of greater than 2.0 mol and 10 mol or less per 1 mol of the charged sulfur source and at the temperature of 245 to 290° C., the polymerization reaction is continued in a phase-separated state, wherein a concentrated phase of the produced polymer and a dilute phase of the produced polymer are co-present as a mixture in the polymerization reaction system. 
 
     
     
       11. The process for producing poly(arylene sulfide) according to  claim 10 , wherein in the second-stage polymerization step, water content in the polymerization reaction system is controlled such that water is present in an amount of greater than 2.0 mol and 10 mol or less per 1 mol of the charged sulfur source and at least one phase separating agent that is selected from the group consisting of metal salts of organic carboxylic acids, metal salts of organic sulfonic acids, alkali metal halides, alkali earth metal halides, alkali earth metal salts of aromatic carboxylic acid, alkali metal salts of phosphoric acid, alcohols, and paraffinic hydrocarbons is included in a range of 0.01 to 3 mol per 1 mol of the charged sulfur source. 
     
     
       12. The process for producing poly(arylene sulfide) according to  claim 1 , wherein, prior to the polymerization step, are arranged
 dehydration step by which a mixture including the organic amide solvent, the sulfur source containing the alkali metal hydrogen sulfide, and alkali metal hydroxide in an amount of 0.95 to 1.05 mol per 1 mol of the alkali metal hydrogen sulfide is reacted by heating and at least part of distillation extract containing water is discharged from inside of the system including the mixture to outside of the system; and 
 charging step by which the alkali metal hydroxide and water are added, if necessary, to the mixture remained in the system after the dehydration step such that total mol number including the mol number of the alkali metal hydroxide that is produced in conjunction with hydrogen sulfide produced by dehydration, the mol number of the alkali metal hydroxide that is added before the dehydration, and the mol number of the alkali metal hydroxide that is added after the dehydration is 1.00 to 1.09 mol per 1 mol of the charged sulfur source and the mol number of water is 0.02 to 2.0 mol per 1 mol of the charged sulfur source.